Alright Iv updated all my drivers and defraged everything on the HD including the registry. However I keep running into the same exact issue. After a few hours of play of sometimes just after a few minutes my display goes black and loses the signal from my tower. Now whatever ambient sound was playing at the time is still there but anything else like gun fire or people talking is gone. Most of the time when I play COD4 the last thing I am left hearing is a helicopter or the rain. The only way I can reproduce this every time is in the Lost Coast bench. Right as the cannon fires on the village I lose signal and everything but one sound. It always causes me to hard restart. I'm really lost as to causing this. Any ideas or advice is welcome!